Background: Myocardial ischemia and infarction are caused by the narrowing of the interior width of the coronary arteries, which is the complex condition known as coronary artery disease (CAD).  Methodology: The diameter of the coronary artery were measured in 140 patients including both genders on CT angiogram. The diameter of proximal left main (LM), the left anterior descending (LAD), left circumflex (LCx), and the right coronary artery (RCA) were measured. Results: Significant variations in the mean diameters of the LM, LAD, LCX, and RCA arteries across the three groups (A-A, A-T, and T-T). The results indicate that the mean diameter of all four coronary arteries is significantly larger in the T-T group compared to the A-T group, which is significantly larger than the A-A group. Conclusion: Transluminal diameter has an significantly on the development of CAD, as this study shows. Reduction transluminal diameter is associated to a higher incidence of CAD, highlighting its significance in the recognition and management of CAD. These findings have consequences for creating individualized treatment plans and enhancing patient outcomes.